The typical wheel of a bicycle comprises a wheel hub connected to a wheel housing. The wheel housing is a ring having an inner wall and an outer wall, and is positioned over the wheel hub. A rubber tire is mounted onto the outer wall of the wheel housing. The wheel hub is positioned at the center of the wheel housing and onto an axle about which the wheel turns. The inner wall of the wheel housing is connected to the wheel hub by spokes. The spokes are rods usually made of stainless steel or other strong material. Typically, a bicycle frame has a front fork, which is for securing a wheel to. The bicycle frame also has a frame rear for securing another wheel to. A typical wheel does not have much shock-absorbing function except for a small amount of cushioning provided by the tire. When the bicycle is being peddled over an uneven stony ground, the bicycle will be subjected to intense bumping which may damage the bicycle frame and may cause much discomfort to the rider. To overcome the damage and discomfort caused by the bumping, a shock absorber is usually mounted on the front fork of the bicycle frame and another shock absorber mounted on the frame rear.
Korean Patent No. KR10-2012-0085689, entitled “” (WHEEL FOR BICYCLE), discloses an improved wheel in which a spring is mounted in the end of each spoke to provide further shock proofing function. When this wheel runs over a stone, the impact causes the spring on the spokes nearest to the ground to be compressed while the springs in the opposite side of the wheel are extended. The shock absorption efficiency of this wheel is affected by the force required to deform the springs on the spokes. However, the improvement in shock absorption provided by the springs on the spokes is relatively small.
FIG. 1A and FIG. 1B illustrates the wheel of German Patent Application No. DE202005011566, entitled “Federsystem für Fahrräder” (SPRING SYSTEM FOR BICYCLE), which discloses another improved wheel in which spring strips are used in place of wheel spokes. The wheel comprises a wheel hub 3 is connected to a midwheel housing. The midwheel housing is in turn connected to a wheel housing 4 via spring strips. The spring strips are typically made of a strong elastic material capable of being deformed resiliently. Each spring strip is in the shape of a spiral, spiraling outwardly in the same direction as the turning of the wheel 4 when the bicycle is cycled forward. A centripetal compression is applied onto the lower spring strips 1 as the wheel rolls on the ground 6. In particular, when the wheel rolls quickly onto an obstacle or protrusion on the ground, the spring strips deforms on being compressed by the protrusion but bounces back to its original shape when the compression force has dissipated. In this way, the spring strips provides shock proofing on a bumpy ground and also provides an energy-storage function. However, as the spring strip is a spiral, the force vector when the spring strip re-bounces to its original shape causes the wheel hub 3 to move towards the center of the wheel 4, and also towards the direction in which the vehicle is moving. This causes the running speed of the vehicle to be increased momentarily and the vehicle will jerk forward. Furthermore, when the lower spring strips 2 are compressed the upper spring strips at the top part of the wheel hub are correspondingly extended. These upper spring strips will also re-bounce back to their original shape when the when the compression force caused by the protrusion has dissipated. Again, as the spring strip is spiral, the force vector of this re-bounce causes the wheel hub 3 to move towards the center of the wheel 4, and also towards the direction in which the vehicle is advancing. The running speed of the vehicle will also be increased momentarily, further jerking the bicycle forward. In other words, the wheel disclosed in DE202005011566 has not only a shockproof function but also stores energy. When the vehicle rides onto an obstacle 5 in front of the vehicle causing deformation of the spring strips, energy is stored in the deformed spring strips which jerks the vehicle forward when released. This erratic change in speed makes it difficult for a driver to control the vehicle.
Accordingly, it is desirable to provide a wheel which has good shock-absorbing effect and which allows a rider or driver to have better control over the speed and direction of the vehicle in which the wheel is installed.